The present invention relates to a control system for a fuel cell vehicle having an exhaust hydrogen combustor, in which it is monitored whether or not the combustion temperature in the exhaust hydrogen combustor is within a prescribed range, for a quick detection of a temperature abnormality in the exhaust hydrogen combustor, to thereby enable an appropriate action to be taken.
In a fuel-cell vehicle of the past, hydrogen was generated by a reformer, from methanol and water, or from methanol, water, and air, and a stack was used to generate electrical power from the hydrogen and air.
In this type of fuel-cell vehicle, the exhaust hydrogen exhausted from the stack was combusted in an exhaust hydrogen combustor, and exhaust heat from the exhaust hydrogen combustor was used to evaporate methanol and water supplied to an evaporator.
The combustion temperature in an exhaust hydrogen combustor was dependent on the amount of exhaust hydrogen from the stack. In fuel-cell vehicles in the past, however, there was no control performed of the temperature in the exhaust hydrogen combustor. If a problem developed in a fuel cell system, it could happen that the combustion temperature in the exhaust hydrogen combustor became excessively low or excessively high.
Given the above-noted problem, it is desirable that the combustion temperature of an exhaust hydrogen combustor be controlled if an abnormal combustion temperature occurs therein. It therefor is an object of the present invention to provide a control system for a fuel cell vehicle having an exhaust hydrogen combustor in which, when an abnormality occurs in the exhaust hydrogen combustor, it is possible to change the control mode of the fuel cell vehicle, thereby contributing to the improvement of the reliability of the fuel-cell vehicle.
An aspect of the present invention to achieve the object is a control system for a fuel cell vehicle equipped with a fuel cell system including a reformer which generates hydrogen from methanol and water and/or air, a fuel cell which generates electrical power from the generated hydrogen and air, and an exhaust hydrogen combustor which combusts exhaust hydrogen exhausted from the fuel cell, the control system comprising a calculator which calculates an amount of hydrogen generated, based on amounts of methanol, water, and air supplied to the reformer and a reaction temperature in the reformer, a calculator which calculates an amount of hydrogen consumed, based on a voltage and a current generated by the fuel cell, a calculator which calculates an amount of hydrogen exhausted by subtracting the consumed amount of hydrogen from the generated amount of hydrogen, a calculator which calculates a combustion temperature in the exhaust hydrogen combustor, based on the exhausted amount of hydrogen, a calculator which calculates a temperature difference between the calculated combustion temperature and a detected temperature of the exhaust hydrogen combustor, a decider which decides that the exhaust hydrogen combustor be abnormal with respect to combustion temperature, when the calculated temperature difference exceeds a first prescribed value, and a controller which controls the fuel cell vehicle to be driven in dependence on a decision of the decider.
According to this aspect of the present invention, the temperature difference between an calculated combustion temperature and a detected temperature is compared with a prescribed reference temperature difference used as a criterion. If this prescribed reference temperature difference is exceeded, a decider makes the judgment that an abnormality has occurred in the combustion temperature, and in response thereto a controller controls the fuel cell vehicle, thereby improving the operating reliability of the fuel cell vehicle.